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Sohei Sukenaga, Pierre Florian, Koji Kanehashi, Hiroyuki Shibata, Noritaka Saito, Kunihiko Nakashima, Dominique Massiot
The description of the structure of aluminosilicate glasses is more often centered on its cationic constituents, and oxygen ions determine their connectivity, directly impacting the physical properties of those disordered materials. A very powerful approach to ascertain this short- to medium-range order is to use (17)O NMR, but up to now the speciation of the chemical bonds was only ambiguously achieved for multicomponent glasses. Here, we propose to directly probe the very scarcely explored through-bond correlations using (17)O{(27)Al} and (17)O{(23)Na} solid-state nuclear magnetic resonance (NMR) double-resonance experiments...
May 8, 2017: Journal of Physical Chemistry Letters
Joshua M Stratford, Martin Mayo, Phoebe K Allan, Oliver Pecher, Olaf J Borkiewicz, Kamila M Wiaderek, Karena W Chapman, Chris J Pickard, Andrew J Morris, Clare P Grey
The alloying mechanism of high-capacity tin anodes for sodium-ion batteries is investigated using a combined theoretical and experimental approach. Ab initio random structure searching (AIRSS) and high-throughput screening using a species-swap method provide insights into a range of possible sodium-tin structures. These structures are linked to experiments using both average and local structure probes in the form of operando pair distribution function analysis, X-ray diffraction, and (23)Na solid-state nuclear magnetic resonance (ssNMR), along with ex situ (119)Sn ssNMR...
May 16, 2017: Journal of the American Chemical Society
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
No abstract text is available yet for this article.
April 1, 2017: Rheumatology
Neal K Bangerter, Grayson J Tarbox, Meredith D Taylor, Joshua D Kaggie
Sodium magnetic resonance imaging (MRI), or imaging of the 23Na nucleus, has been under exploration for several decades, and holds promise for potentially revealing additional biochemical information about the health of tissues that cannot currently be obtained from conventional hydrogen (or proton) MRI. This additional information could serve as an important complement to conventional MRI for many applications. However, despite these exciting possibilities, sodium MRI is not yet used routinely in clinical practice, and will likely remain strictly in the domain of exploratory research for the coming decade...
December 2016: Quantitative Imaging in Medicine and Surgery
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
Objective.: Skin fibrosis is the predominant feature of SSc and arises from excessive extracellular matrix deposition. Glycosaminoglycans are macromolecules of the extracellular matrix, which facilitate Na + accumulation in the skin. We used 23 Na-MRI to quantify Na + in skin. We hypothesized that skin Na + might accumulate in SSc and might be a biomarker for skin fibrosis. Methods.: In this observational case-control study, skin Na + was determined by 23 Na-MRI using a Na + volume coil in 12 patients with diffuse cutaneous SSc and in 21 control subjects...
April 1, 2017: Rheumatology
Zoë E M Reeve, Christopher J Franko, Kristopher J Harris, Hossein Yadegari, Xueliang Sun, Gillian R Goward
(23)Na MAS NMR spectra of sodium-oxygen (Na-O2) cathodes reveals a combination of degradation species: newly observed sodium fluoride (NaF) and the expected sodium carbonate (Na2CO3), as well as the desired reaction product sodium peroxide (Na2O2). The initial reaction product, sodium superoxide (NaO2), is not present in a measurable quantity in the (23)Na NMR spectra of the cycled electrodes. The reactivity of solid NaO2 is probed further, and NaF is found to be formed through a reaction between the electrochemically generated NaO2 and the electrode binder, polyvinylidene fluoride (PVDF)...
January 18, 2017: Journal of the American Chemical Society
James C Pramudita, Aditya Rawal, Mohammad Choucair, Daniele Pontiroli, Giacomo Magnani, Mattia Gaboardi, Mauro Riccò, Neeraj Sharma
Two chemically synthesized defective graphene materials with distinctly contrasting extended structures and surface chemistry are used to prepare sodium-ion battery electrodes. The difference in electrode performance between the chemically prepared graphene materials is qualified based on correlations with intrinsic structural and chemical dissimilarities. The overall effects of the materials' physical and chemical discrepancies are quantified by measuring the electrode capacities after repeated charge/discharge cycles...
December 28, 2016: ACS Applied Materials & Interfaces
Donato Belmonte, Carlo Gatti, Giulio Ottonello, Pascal Richet, Marino Vetuschi Zuccolini
Thermodynamic and thermophysical properties of Na2SiO3 in the Cmc21 structural state are computed ab initio using the hybrid B3LYP density functional method. The static properties at the athermal limit are first evaluated through a symmetry-preserving relaxation procedure. The thermodynamic properties that depend on vibrational frequencies, viz., heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, and Gibbs free energy, are then computed in the framework of quasi-harmonic approximation...
November 10, 2016: Journal of Physical Chemistry. A
Johannes Budjan, Urs Benck, Alexander Lammert, Melissa M Ong, Miryana Mircheva, Steffen Diehl, Simon Konstandin, Lothar R Schad, Bernhard K Krämer, Stefan O Schoenberg, Stefan Haneder
BACKGROUND/AIM: Renal denervation (RDN) has been considered a promising therapy option for patients suffering from therapy-resistant hypertension. Besides, in blood-pressure regularization, the kidneys play a fundamental role in sodium ((23)Na) homeostasis. This study assesses the effect of RDN on renal (23)Na concentration using (23)Na magnetic resonance imaging (MRI). PATIENTS AND METHODS: Two patients with therapy-resistant hypertension underwent RDN. (23)Na-MRI, (1)H-MRI, including diffusion weighted imaging (DWI), as well as endothelial dysfunction assessment, were performed 1 day prior, as well as 1, 30 and 90 days after RDN...
September 2016: In Vivo
Eva Sperling, Kamil Górecki, Torbjörn Drakenberg, Cecilia Hägerhäll
It has long been known that the three largest subunits in the membrane domain (NuoL, NuoM and NuoN) of complex I are homologous to each other, as well as to two subunits (MrpA and MrpD) from a Na+/H+ antiporter, Mrp. MrpA and NuoL are more similar to each other and the same is true for MrpD and NuoN. This suggests a functional differentiation which was proven experimentally in a deletion strain model system, where NuoL could restore the loss of MrpA, but not that of MrpD and vice versa. The simplest explanation for these observations was that the MrpA and MrpD proteins are not antiporters, but rather single subunit ion channels that together form an antiporter...
2016: PloS One
Ying Yan, Chuanbao Zhang, Jiangtao Zhang, Tianjiao Zhang, Weiyan Zhou, Jie Zeng, Wenxiang Chen
BACKGROUND: Serum sodium and magnesium are important clinical laboratory tests and accurate testing results are needed for the correct interpretation of the tests. Standardization of serum sodium and magnesium measurements requires simple and reliable reference methods. METHODS: Inductively coupled plasma mass spectrometry (ICP-MS) methods for the measurement of serum sodium and magnesium were developed. Aluminum was used as an internal standard. Serum samples were spiked with the internal standard, digested with 69% nitric acid at 150 degrees C and measured for 23Na/27Al and 24Mg/27Al ratios by ICP-MS...
2016: Clinical Laboratory
Jiri Brus, Libor Kobera, Martina Urbanova, Barbora Doušová, Miloslav Lhotka, David Koloušek, Jiří Kotek, Pavel Čuba, Jiri Czernek, Jiří Dědeček
Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix...
March 22, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
A V Uskov, D Yu Nefedov, E V Charnaya, J Haase, D Michel, Yu A Kumzerov, A V Fokin, A S Bugaev
(23)Na NMR studies of sodium nanoparticles confined to porous glass with the 3.5 nm mean pore size were carried out. The emergence of the second component of the NMR line was observed below 240 K that evidences the occurrence of another modification of metallic sodium. The phase transition temperature is much higher than the martensite transformation temperature in bulk sodium.
January 13, 2016: Nano Letters
Philipp Eisele, Simon Konstandin, Martin Griebe, Kristina Szabo, Marc E Wolf, Angelika Alonso, Anne Ebert, Julia Serwane, Christina Rossmanith, Michael G Hennerici, Lothar R Schad, Achim Gass
BACKGROUND: Advanced magnetic resonance imaging (MRI) techniques provide a window into pathological processes in multiple sclerosis (MS). Nevertheless, to date only few studies have performed sodium MRI in MS. OBJECTIVES: We analysed total sodium concentration (TSC) in hyperacute, acute and chronic lesions in MS with (23)Na MRI. METHODS: (23)Na MRI and (1)H MRI were performed in 65 MS patients and 10 healthy controls (HC). Mean TSC was quantified in all MS lesions with a diameter of >5 mm and in the normal appearing white and grey matter (NAWM, NAGM)...
July 2016: Multiple Sclerosis: Clinical and Laboratory Research
Renny Mathew, Baltzar Stevensson, Mattias Edén
We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR...
April 30, 2015: Journal of Physical Chemistry. B
Eduardo M Bruch, Melissa T Warner, Sébastien Thomine, Leandro C Tabares, Sun Un
The ability to characterize the structure of metal centers beyond their primary ligands is important to understanding their chemistry. High-magnetic-field pulsed electron double resonance detected NMR (ELDOR-NMR) is shown to be a very sensitive approach to measuring the multinuclear NMR spectra of the nuclei surrounding Mn(II) ions. Resolved spectra of intact organisms with resonances arising from (55)Mn, (31)P, (1)H, (39)K, (35)Cl, (23)Na, and (14)N nuclei surrounding Mn(2+) centers were obtained. Naturally abundant cellular (13)C could be routinely measured as well...
October 29, 2015: Journal of Physical Chemistry. B
Yan Fang, Bo Duan, Ang Lu, Maili Liu, Huili Liu, Xiaojuan Xu, Lina Zhang
The intra- and intermolecular interactions of chitin in NaOH/urea aqueous system were studied by a combination of NMR measurements (including (13)C NMR, (23)Na NMR, and (15)N NMR) and differential scanning calorimetry. The results revealed that the NaOH and chitin formed a hydrogen-bonded complex that was surrounded by the urea hydrates to form a sheath-like structure, leading to the good dissolution. The optimal concentration range, in which chitin was molecularly dispersed in NaOH/urea aqueous, was found to investigate the chain conformation in the dilute solution with a combination of static and dynamic light scattering...
April 13, 2015: Biomacromolecules
Mario Ronga, Gloria Angeretti, Sergio Ferraro, Giovanni DE Falco, Eugenio A Genovese, Paolo Cherubino
Magnetic resonance imaging (MRI) is the gold standard method for non-invasive assessment of joint cartilage, providing information on the structure, morphology and molecular composition of this tissue. There are certain minimum requirements for a MRI study of cartilage tissue: machines with a high magnetic field (> 1.5 Tesla); the use of surface coils; and the use of T2-weighted, proton density-weighted fast-spin echo (T2 FSE-DP) and 3D fat-suppressed T1-weighted gradient echo (3D-FS T1W GRE) sequences. For better contrast between the different joint structures, MR arthography is a method that can highlight minimal fibrillation or fractures of the articular surface and allow evaluation of the integrity of the native cartilage-repair tissue interface...
July 2014: Joints
Christine Gnahm, Armin M Nagel
Sodium ((23)Na) MRI is a noninvasive tool to assess cell viability, which is linked to the total tissue sodium concentration (TSC). However, due to low in vivo concentrations, (23)Na MRI suffers from low signal-to-noise ratio (SNR) and limited spatial resolution. As a result, image quality is compromised by Gibbs ringing artifacts and partial volume effects. An iterative reconstruction algorithm that incorporates prior information from (1)H MRI is developed to reduce partial volume effects and to increase the SNR in non-proton MRI...
January 15, 2015: NeuroImage
Ronald Pawl
This commentary evaluates four articles dealing with chronic pain from very different perspectives. The first paper by Tsantoulas and McMahon entitled "Opening paths to novel analgesics: the role of potassium channels in chronic pain" evaluates the membrane neurochemistry of the neural cells governing the transmission of pain impulses in the spinal cord and trigeminal systems. As potassium membrane potentials diminish excitability in the nociceptive pain pathways, damage to these pathways may result in excessive transmission of impulses that contribute to "chronic pain"...
2014: Surgical Neurology International
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